"In order to establish self-defense, a defendant has to prove that (1) he was not at fault in creating the situation giving rise to the affray, (2) he had reasonable grounds to believe and an honest belief that he was in immediate danger of death or great bodily harm and that his only means of escape from such danger was by the use of force, and (3) he had not violated any duty to escape to avoid the danger. . . . A defendant is privileged to use only that force that is reasonably necessary to repel the attack." State v. Hendrickson, 2009 Ohio 4416
There is no duty to retreat when defending one's self or others in one's home or vehicle. Deadly force maybe used when an aggressor is illegally entering one's home or vehicle.